I just purchased a 930 JM pro tactical class. I've been informed that the gas piston in this particular model has a nickel boron coating. So my question is. Is it safe to soak the whole gas piston in hopes #9 over night? I don't wanna damage the coating..
Ed's Red you can make yourself for about ten bucks a gallon, enough to last your natural lifetime with four simple ingredients. Great for soaking gas pistons since at that price you can pour it into a deep receptacle and drop parts in. Cleans the heck out of lots and lots of gun parts. Won't strip finishes, is plastic safe, and even prevents rust for a little while.
Look it up. I leave out the fifth ingredient (lanolin).
If you want to reduce cleaning, and get the ultimate long term reliability get an SBE Precision Products stainless steel competition piston. Not only do they not corrode at all, but the new piston significantly lengthens cleaning intervals, and makes cleaning very easy since it only uses a single outer piston ring. The picture below is after 2000 shells fired without cleaning.